This invention relates to machines such as sewing machines, tufting machines, knitting machines and weaving machines wherein a thread is consumed at a work station, and deals more particularly with such a machine having combined with it a means for selectively varying the color of a thread used by the machine and for causing a change in thread color to arrive at the work station at a desired time in the work schedule. The invention also concerns a related process for operating a thread consuming machine in combination with a thread color varying device.
The invention is illustrated and described herein in connection with a sewing machine in which application it is advantageously used for doing embroidery or other decorative stitching on workpieces, such as leather shoe parts or fabric clothing parts, requiring a number of different thread colors. In such case the sewing machine, a thread color device, a workpiece moving mechanism and other components of the overall system may all be under computer control so that an entire schedule of work, including one or more changes of thread color, is performed automatically without operator intervention, but such complete automation is not necessary and instead movement of the workpiece relative to the work station and other functions and operations in the work schedule may be performed manually. Although the invention has considerable utility when used in conjunction with a sewing machine, it should be understood that in its broader aspects the invention is not limited to a sewing machine and is equally applicable to a tufting machine, a knitting machine, a weaving machine or any other machine consuming thread at a work station and performing a schedule of work at the work station which desirably includes one or more changes in thread color.
The general idea of combining a thread color device with a thread consuming machine is known from prior U.S. Pat. Nos. 2,310,764; 2,712,297; and 3,620,662. In each of these prior patents, however, there is no means or process for coordinating the operation of the color device with the schedule of work performed at the work station, or of controlling the movement of the thread from the color device to the work station, to cause a color change to occur at the work station at a desired time in the work schedule.
The general object of the invention is therefore to provide an improved combination of a thread consuming machine and a thread color varying device which combination is capable of performing a schedule of work at a work station without need for rethreading the machine to make thread color changes and wherein such thread color changes are made by changing the color of a single supply thread before it reaches the work station.
A further object of the invention is to provide a combination of the foregoing character, and a related process, wherein the operation of the thread color device is coordinated with the schedule of work performed at the work station and with the movement of the thread from the color device to the work station so that a change in thread color arrives at the work station at a desired time in the work schedule.
A still further object of the invention is to provide a thread consuming machine of the foregoing character, and a related process, whereby an entire schedule of work may be automatically performed at the work station without operator intervention.
A further object of the invention is to provide a thread consuming machine and related process of the foregoing character whereby sections of thread containing transitions from one color to another are stitched on waste portions of the workpiece or otherwise dealt with so as not to appear as blemishes in the finished product.
Other objects and advantages of the invention will be apparent from the following detailed description of the preferred embodiments of the invention.